Burners are used, for example, in apparatuses including furnaces and appliances such as clothes dryers. A principle component of burners is a nozzle typically in the form of a venturi tube. Combustible gas is fed into the nozzle and entrains air into the nozzle. The air and gas is mixed in the venturi and the mixture emerges from the outlet end. An igniter may be attached directly to the venturi tube in front of the outlet opening in alignment with a longitudinal axis along which the nozzle extends and ignites the mixture as it leaves the outlet, thereby creating flame which produces heat that is utilized by the apparatus.
In furnaces, a plurality of burner nozzles are typically arranged side-by-side and are designed for cross-ignition of the gas in adjacent nozzles. One conventional nozzle has two plenum chambers located at an outlet end of the venturi tube. Each plenum chamber has a thin outlet slit along its side edges. Flame released from the side outlet slits of one nozzle ignites gas from an adjacent nozzle.
Clothes dryer burners may be horizontally fired into ducts of the dryer. The ducts shield the open flame and force the heated gases in the desired direction. The burner may include an attachment known as a flame spreader which is separately formed from the nozzle, mounted such as by welding to the nozzle and axially spaced from the outlet opening of the nozzle. Flame spreaders shorten and spread out the flame transverse to a direction of gas flow. The flame spreaders are disposed in the flame and thus, are exposed to relatively high temperatures. This requires the flame spreaders to be fabricated from metals which can withstand this high temperature environment.
Conventional gas dryer burner nozzles typically produce flame having a length of, for example, about one foot. However, space is limited in the dryer. Long flame lengths may result in inefficient heat transfer between the flame and air inside the ductwork, overheating of the ductwork, or an increase in the cost of the dryer due to the use of enough ductwork and other components to accommodate the long flame. Heated gases from the horizontal flame are typically directed through a 90.degree. elbow, generally vertically to another 90.degree. elbow, through a screen and then into a rotatable drum in which clothes are dried. An air blower may be disposed upstream or downstream of the burner for directing air in the drum of the dryer.
Typical gas dryer burner nozzles can be difficult and relatively expensive to manufacture. Generally, such burner nozzles are fabricated by a practice of shaping the body from tubing and attaching flame spreaders and brackets by welding. Another problem with conventional dryer burner applications is that they are susceptible to igniter breakage. More specifically, the igniters are connected directly to the burner nozzle and, being fragile, may crack or break off during shipping and handling.